Upload modeling_ovis.py

modeling_ovis.py

@@ -0,0 +1,590 @@
+# Copyright (C) 2025 AIDC-AI
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import logging
+import os
+import importlib.metadata
+
+from packaging import version
+from importlib import import_module
+from typing import List, Callable, Union, Optional, Dict
+
+import PIL.Image
+import torch
+from torch import Tensor
+from torch.nn import init
+from torch.nn.functional import softmax, gumbel_softmax, pad
+from transformers.utils import is_flash_attn_2_available
+from transformers import PreTrainedModel, AutoModel, AutoTokenizer, AutoModelForCausalLM, AutoImageProcessor
+from transformers.generation.utils import GenerateOutput
+
+from .configuration_ovis import BaseVisualTokenizerConfig, Aimv2VisualTokenizerConfig
+from .configuration_ovis import OvisConfig, ConversationFormatter
+from .configuration_ovis import IGNORE_ID, IMAGE_ATOM_ID, IMAGE_INDICATOR_IDS, IMAGE_TOKEN_ID
+
+# ----------------------------------------------------------------------
+#                            Visual Tokenizer
+# ----------------------------------------------------------------------
+class BaseVisualTokenizer(PreTrainedModel):
+    base_model_prefix = "backbone"
+    main_input_name = None
+    _image_processor_class = None
+    _image_processor_kwargs = {}
+    _backbone_class = None
+    _backbone_name_or_path = None
+
+    def __init__(self, config: BaseVisualTokenizerConfig, *inputs, **kwargs):
+        super().__init__(config, *inputs, **kwargs)
+        self.image_processor = AutoImageProcessor.from_pretrained(kwargs['image_processor_name_or_path'])
+        self.backbone = AutoModel.from_config(self.config.backbone_config)
+        head_dim = self.config.vocab_size - len(IMAGE_INDICATOR_IDS)  # reserved tokens for IMAGE_INDICATORS
+        self.head = torch.nn.Sequential(
+            torch.nn.Linear(
+                self.backbone.config.hidden_size * self.config.hidden_stride * self.config.hidden_stride, head_dim,
+                bias=False
+            ),
+            torch.nn.LayerNorm(head_dim)
+        )
+
+        assert all((self.image_processor.do_resize,
+                    not getattr(self.image_processor, 'do_center_crop', False),
+                    self.image_processor.do_rescale,
+                    self.image_processor.do_normalize
+                    )), f"image_processor `{self.image_processor}` is not supported currently"
+
+    def get_backbone(self):
+        return self.backbone
+
+    def get_image_processor(self):
+        return self.image_processor
+
+    def mock_input(self):
+        height, width = self.get_image_size()
+        return torch.zeros(1, 3, height, width), self.construct_image_placeholders((1, 1))
+
+    def get_head(self):
+        return self.head
+
+    def get_image_size(self):
+        raise NotImplementedError
+
+    @staticmethod
+    def construct_image_placeholders(grid):
+        image_placeholders = [IMAGE_INDICATOR_IDS[0], IMAGE_ATOM_ID, IMAGE_INDICATOR_IDS[1]]
+        if grid[0] * grid[1] > 1:
+            for r in range(grid[0]):
+                for c in range(grid[1]):
+                    image_placeholders.append(IMAGE_ATOM_ID)
+                    if c < grid[1] - 1:
+                        image_placeholders.append(IMAGE_INDICATOR_IDS[2])
+                if r < grid[0] - 1:
+                    image_placeholders.append(IMAGE_INDICATOR_IDS[3])
+        image_placeholders.append(IMAGE_INDICATOR_IDS[4])
+        return image_placeholders
+
+    def preprocess_image(self, image: PIL.Image.Image, max_partition=9, covering_threshold=0.9, convert_to_rgb=True):
+        def _preprocess(img: PIL.Image.Image, side):
+            # first resize and preprocess
+            w, h = img.size
+            if w == h:
+                new_width = new_height = side
+            elif w > h:
+                new_width = side
+                new_height = int(h / w * new_width)
+            else:
+                new_height = side
+                new_width = int(w / h * new_height)
+            new_size = dict(height=new_height, width=new_width)
+            pixel_values = self.image_processor.preprocess(img, size=new_size, return_tensors='pt')['pixel_values']
+
+            # then pad to square
+            square_values = torch.zeros([1, 3, side, side], dtype=pixel_values.dtype, device=pixel_values.device)
+            new_height, new_width = pixel_values.shape[2:]
+            if new_height == new_width:
+                square_values[:, :, :, :] = pixel_values
+            elif new_height > new_width:
+                from_index = (side - new_width) // 2
+                square_values[:, :, :, from_index:from_index + new_width] = pixel_values
+            else:
+                from_index = (side - new_height) // 2
+                square_values[:, :, from_index:from_index + new_height, :] = pixel_values
+
+            return square_values
+
+        def _partition(img, grid):
+            w, h = img.size
+            row_height = h // grid[0]
+            col_width = w // grid[1]
+
+            partition = []
+            for row in range(grid[0]):
+                for col in range(grid[1]):
+                    left = col * col_width
+                    upper = row * row_height
+                    right = w if col == grid[1] - 1 else (col + 1) * col_width
+                    lower = h if row == grid[0] - 1 else (row + 1) * row_height
+                    partition.append((left, upper, right, lower))
+
+            return partition
+
+        def _covering_area(left, upper, right, lower, side):
+            w = right - left
+            h = lower - upper
+            w, h = max(w, h), min(w, h)
+            if w > side:
+                h = h / w * side
+                w = side
+            return w * h
+
+        def _get_best_grid(img, side):
+            img_area = img.size[0] * img.size[1]
+
+            candidate_grids = []
+            for i in range(1, max_partition + 1):
+                for j in range(1, max_partition + 1):
+                    if i * j <= max_partition:
+                        candidate_grids.append((i, j))
+
+            all_grids = []
+            good_grids = []
+            for grid in candidate_grids:
+                partition = _partition(img, grid)
+                covering_ratio = sum([_covering_area(*p, side) for p in partition]) / img_area
+                assert covering_ratio <= 1.0
+                all_grids.append((grid, covering_ratio))
+                if covering_ratio > covering_threshold:
+                    good_grids.append((grid, covering_ratio))
+
+            if len(good_grids) > 0:
+                # pick the good partition with minimum #sub_images and break the tie using covering_ratio
+                return sorted(good_grids, key=lambda x: (x[0][0] * x[0][1], -x[1]))[0][0]
+            else:
+                # pick the partition with maximum covering_ratio and break the tie using #sub_images
+                return sorted(all_grids, key=lambda x: (-x[1], x[0][0] * x[0][1]))[0][0]
+
+        if convert_to_rgb and image.mode != 'RGB':
+            image = image.convert('RGB')
+
+        sides = self.get_image_size()
+        if sides[0] != sides[1]:
+            raise ValueError('get_image_size() returns non-square size')
+        side = sides[0]
+        grid = _get_best_grid(image, side)
+        partition = _partition(image, grid)
+        crops = [image.crop(p) for p in partition]
+        if len(crops) > 1:
+            crops.insert(0, image)
+        pixel_values = torch.cat([_preprocess(crop, side) for crop in crops], dim=0)
+        image_placeholders = self.construct_image_placeholders(grid)
+        return pixel_values, image_placeholders
+
+    def tokenize(self, logits):
+        def st_argmax(y_soft, dim):  # straight-through softmax
+            index = y_soft.max(dim, keepdim=True)[1]
+            y_hard = torch.zeros_like(y_soft, memory_format=torch.legacy_contiguous_format).scatter_(dim, index, 1.0)
+            ret = y_hard - y_soft.detach() + y_soft
+            return ret
+
+        if self.config.tokenize_function == 'softmax':
+            tokens = softmax(logits, dim=-1)
+        elif self.config.tokenize_function == 'gumbel_argmax':
+            tokens = gumbel_softmax(logits, tau=self.config.tau, hard=True)
+        elif self.config.tokenize_function == 'st_argmax':
+            tokens = st_argmax(logits, dim=-1)
+        else:
+            raise ValueError(
+                f'Invalid `max_type`, expected softmax or gumbel_argmax or st_argmax, but got {self.config.tokenize_function}')
+        return tokens
+
+    def encode(self, pixel_values):
+        output = self.backbone(pixel_values, output_hidden_states=True, return_dict=True)
+        features = output.hidden_states[-1]
+        if self.config.drop_cls_token:
+            features = features[:, 1:, :]
+
+        # merge number of `hidden_stride * hidden_stride` hidden states together to reduce token sequence length
+        # e.g., for hidden_stride=2, this leads to a token length reduction: 1024 -> 256 for aimv2
+        if self.config.hidden_stride > 1:
+            n, l, d = features.shape  # this `d` maybe different from the above `d
+            sqrt_l = int(l ** 0.5)
+            assert sqrt_l ** 2 == l, "The token sequence length should be a perfect square."
+            features = features.reshape(n, sqrt_l, sqrt_l, d)
+            pl = (self.config.hidden_stride - (sqrt_l % self.config.hidden_stride)) % self.config.hidden_stride
+            features = pad(features, (0, 0, 0, pl, 0, pl), "constant", 0)
+            sqrt_l += pl
+            features = features.reshape(n, sqrt_l // self.config.hidden_stride, self.config.hidden_stride,
+                                        sqrt_l // self.config.hidden_stride, self.config.hidden_stride, d)
+            features = features.permute(0, 1, 3, 2, 4, 5)  # [n, sqrt_l/hs, sqrt_l/hs, hs, hs, d]
+            features = features.flatten(3)  # [n, sqrt_l/hs, sqrt_l/hs, hs*hs*d]
+            features = features.reshape(
+                n, -1, self.config.hidden_stride * self.config.hidden_stride * d)
+
+        return features
+
+    def forward(self, pixel_values) -> torch.Tensor:  # [BatchSize, ImageShape] -> [BatchSize, #Token, VocabSize]
+        features = self.encode(pixel_values)
+        logits = self.head(features)
+        tokens = self.tokenize(logits)
+        # tokens' shape is [BatchSize, #Token, VocabSize-5], so padding with [BatchSize, #Token, 5], after
+        # which, tokens' shape should become [BatchSize, #Token, VocabSize]
+        batch_size, token_len, _ = tokens.shape
+        padding_tensor = torch.zeros(size=(batch_size, token_len, len(IMAGE_INDICATOR_IDS)),
+                                     dtype=tokens.dtype,
+                                     device=tokens.device,
+                                     layout=tokens.layout,
+                                     requires_grad=False)
+        tokens = torch.cat((tokens, padding_tensor), dim=2)
+        return tokens
+
+
+class Aimv2VisualTokenizer(BaseVisualTokenizer):
+    config_class = Aimv2VisualTokenizerConfig
+    supports_gradient_checkpointing = True
+    _no_split_modules = ["AIMv2ViTPreprocessor", "AIMv2Block"]
+    _image_processor_kwargs = dict(do_center_crop=False)
+
+    def get_image_size(self):
+        height = self.image_processor.crop_size["height"]
+        width = self.image_processor.crop_size["width"]
+        return height, width
+
+
+AutoModel.register(Aimv2VisualTokenizerConfig, Aimv2VisualTokenizer)
+
+
+# ----------------------------------------------------------------------
+#                                  Ovis
+# ----------------------------------------------------------------------
+class VisualEmbedding(torch.nn.Embedding):
+    def forward(self, visual_tokens: Tensor) -> Tensor:
+        if visual_tokens.dtype in [torch.int8, torch.int16, torch.int32, torch.int64, torch.long]:
+            return super().forward(visual_tokens)
+        return torch.matmul(visual_tokens, self.weight)
+
+    def reset_parameters(self, mean=0., std=1.) -> None:
+        init.normal_(self.weight, mean=mean, std=std)
+        self._fill_padding_idx_with_zero()
+
+
+class OvisPreTrainedModel(PreTrainedModel):
+    config_class = OvisConfig
+    base_model_prefix = "ovis"
+
+
+class Ovis(OvisPreTrainedModel):
+
+    def __init__(self, config: OvisConfig, *inputs, **kwargs):
+        super().__init__(config, *inputs, **kwargs)
+        attn_kwargs = dict()
+        if self.config.llm_attn_implementation:
+            if self.config.llm_attn_implementation == "flash_attention_2":
+                assert (is_flash_attn_2_available() and
+                        version.parse(importlib.metadata.version("flash_attn")) >= version.parse("2.6.3")), \
+                    "Using `flash_attention_2` requires having `flash_attn>=2.6.3` installed."
+            attn_kwargs["attn_implementation"] = self.config.llm_attn_implementation
+        self.llm = AutoModelForCausalLM.from_config(self.config.llm_config, **attn_kwargs)
+        assert self.config.hidden_size == self.llm.config.hidden_size, "hidden size mismatch"
+        self.text_tokenizer = AutoTokenizer.from_pretrained(self.config.name_or_path)
+        self.visual_tokenizer = AutoModel.from_config(self.config.visual_tokenizer_config,
+                                                      image_processor_name_or_path=self.config.name_or_path)
+        self.vte = VisualEmbedding(
+            self.config.visual_tokenizer_config.vocab_size,
+            self.config.hidden_size,
+            device=self.visual_tokenizer.device,
+            dtype=self.visual_tokenizer.dtype
+        )
+
+        def _merge_modules(modules_list: tuple):
+            merged_modules = []
+            for modules in modules_list:
+                merged_modules.extend(modules if modules else [])
+            return merged_modules
+
+        self._no_split_modules = _merge_modules((self.llm._no_split_modules, self.visual_tokenizer._no_split_modules))
+        self._skip_keys_device_placement = self.llm._skip_keys_device_placement
+        self._keep_in_fp32_modules = _merge_modules(
+            (self.llm._keep_in_fp32_modules, self.visual_tokenizer._keep_in_fp32_modules))
+        self.is_parallelizable = all((self.llm.is_parallelizable, self.visual_tokenizer.is_parallelizable))
+        self.supports_gradient_checkpointing = True
+        self._supports_flash_attn_2 = True
+
+    def get_text_tokenizer(self):
+        return self.text_tokenizer
+
+    def get_visual_tokenizer(self):
+        return self.visual_tokenizer
+
+    def tie_weights(self):
+        if not self.config.disable_tie_weight:
+            self.get_llm().tie_weights()
+
+    def get_llm(self):
+        return self.llm
+
+    def get_vte(self):
+        return self.vte
+
+    def get_wte(self):
+        return self.llm.get_input_embeddings()
+
+    def get_conversation_formatter(self) -> ConversationFormatter:
+        if getattr(self, 'conversation_formatter', None) is None:
+            self.conversation_formatter = getattr(import_module(".configuration_ovis", __package__),
+                                                  self.config.conversation_formatter_class)(self.text_tokenizer)
+        return self.conversation_formatter
+
+    def forward(
+        self,
+        input_ids: torch.Tensor,
+        attention_mask: torch.Tensor,
+        labels: Optional[torch.Tensor],
+        pixel_values: List[Optional[torch.Tensor]],
+        **kwargs
+    ):
+        # assert self.training, "`forward` can only be used in training. For inference, use `generate`."
+        _, inputs_embeds, labels, attention_mask = self.merge_multimodal(
+            text_input_ids=input_ids,
+            text_attention_masks=attention_mask,
+            text_labels=labels,
+            pixel_values=pixel_values
+        )
+        return self.llm(inputs_embeds=inputs_embeds, labels=labels, attention_mask=attention_mask, **kwargs)
+
+    def merge_multimodal(
+        self,
+        text_input_ids: torch.Tensor,
+        text_attention_masks: torch.Tensor,
+        text_labels: Optional[torch.Tensor],
+        pixel_values: List[Optional[torch.Tensor]],
+        left_padding: bool = False
+    ):
+        input_device = text_input_ids.device
+        visual_vocab_szie = self.get_visual_tokenizer().config.vocab_size
+        visual_indicator_embeds = self.get_vte()(
+            torch.tensor(
+                list(range(visual_vocab_szie - 5, visual_vocab_szie)),
+                dtype=torch.long,
+                device=self.get_visual_tokenizer().device
+            )
+        ).to(device=input_device)
+
+        if self.training:
+            # When training, to be compatible with deepspeed zero, each sample has to include pixel_value tensor.
+            # For text-only sample, one can simply use a full zero tensor as pixel_value, which will be ignored
+            # (see below in this function); so, the gradient will not be affected.
+            num_images = [x.shape[0] for x in pixel_values]
+            visual_tokens = self.visual_tokenizer(torch.cat([x for x in pixel_values], dim=0))
+            visual_embeds = torch.split(self.get_vte()(visual_tokens).to(dtype=self.dtype, device=input_device),
+                                        split_size_or_sections=num_images, dim=0)
+            visual_input_ids = torch.split(torch.argmax(visual_tokens, dim=-1).to(device=input_device),
+                                           split_size_or_sections=num_images, dim=0)
+            visual_labels = [torch.full(x.shape, IGNORE_ID, dtype=torch.long, device=input_device) for x in
+                             visual_input_ids]
+        else:
+            # When inference, sample can include only text with `None` pixel_value
+            num_images = [x.shape[0] if x is not None else 0 for x in pixel_values]
+            if sum(num_images) > 0:
+                visual_tokens = self.visual_tokenizer(torch.cat([x for x in pixel_values if x is not None], dim=0))
+                visual_embeds = torch.split(self.get_vte()(visual_tokens).to(dtype=self.dtype, device=input_device),
+                                            split_size_or_sections=num_images, dim=0)
+                visual_input_ids = torch.split(torch.argmax(visual_tokens, dim=-1).to(device=input_device),
+                                               split_size_or_sections=num_images, dim=0)
+                visual_labels = [torch.full(x.shape, IGNORE_ID, dtype=torch.long, device=input_device) for x in
+                                 visual_input_ids]
+            else:
+                # just placeholders
+                visual_embeds = [None] * len(num_images)
+                visual_input_ids = [None] * len(num_images)
+                visual_labels = [None] * len(num_images)
+        # just placeholders
+        if text_labels is None:
+            text_labels = torch.full(text_input_ids.shape, IGNORE_ID, dtype=torch.long, device=input_device)
+
+        input_embeds = []
+        attention_masks = []
+        labels = []
+        for text_input_id, text_label, text_attention_mask, visual_embed, visual_input_id, visual_label in zip(
+                text_input_ids, text_labels, text_attention_masks, visual_embeds, visual_input_ids, visual_labels
+        ):
+            placeholder_token_mask = torch.lt(text_input_id, 0)
+            text_embed = self.get_wte()(torch.masked_fill(text_input_id, placeholder_token_mask, 0))
+            for i, indicator_id in enumerate(IMAGE_INDICATOR_IDS):
+                text_embed[text_input_id == indicator_id] = visual_indicator_embeds[i]
+            image_atom_positions = torch.where(torch.eq(text_input_id, IMAGE_ATOM_ID))[0].tolist()
+            if len(image_atom_positions) > 0:
+                input_embed_parts = []
+                attention_mask_parts = []
+                label_parts = []
+                prev_image_atom_position = -1
+                for index, image_atom_position in enumerate(image_atom_positions):
+                    input_embed_parts.append(
+                        text_embed[prev_image_atom_position + 1:image_atom_position, :])
+                    label_parts.append(
+                        text_label[prev_image_atom_position + 1:image_atom_position])
+                    attention_mask_parts.append(
+                        text_attention_mask[prev_image_atom_position + 1:image_atom_position])
+                    input_embed_parts.append(visual_embed[index])
+                    attention_mask_parts.append(
+                        torch.ones_like(visual_label[index], dtype=torch.bool))
+                    label_parts.append(visual_label[index])
+                    prev_image_atom_position = image_atom_position
+                if prev_image_atom_position + 1 < text_input_id.shape[0]:
+                    input_embed_parts.append(
+                        text_embed[prev_image_atom_position + 1:, :])
+                    attention_mask_parts.append(
+                        text_attention_mask[prev_image_atom_position + 1:])
+                    label_parts.append(
+                        text_label[prev_image_atom_position + 1:])
+                input_embed = torch.cat(input_embed_parts, dim=0)
+                attention_mask = torch.cat(attention_mask_parts, dim=0)
+                label = torch.cat(label_parts, dim=0)
+            else:
+                input_embed = text_embed
+                attention_mask = text_attention_mask
+                label = text_label
+                if self.training:
+                    # Make visual_embed & visual_indicator_embeds involved in the backward graph,
+                    # to be compatible with deepspeed zero and ddp.
+                    input_embed += torch.sum(visual_embed * 0.0) + torch.sum(visual_indicator_embeds * 0.0)
+            input_embeds.append(input_embed)
+            attention_masks.append(attention_mask)
+            labels.append(label)
+
+        if self.training:  # padding to self.config.multimodal_max_length for increased training speed
+            padding_size = max(0, self.config.multimodal_max_length - len(input_embeds[0]))
+            input_embeds[0] = torch.nn.ConstantPad2d((0, 0, 0, padding_size), 0.0)(input_embeds[0])
+            attention_masks[0] = torch.nn.ConstantPad1d((0, padding_size), False)(attention_masks[0])
+            labels[0] = torch.nn.ConstantPad1d((0, padding_size), IGNORE_ID)(labels[0])
+        batch_input_embeds = self.pad_truncate_sequence(input_embeds, batch_first=True, padding_value=0.0, left_padding=left_padding)
+        batch_attention_mask = self.pad_truncate_sequence(attention_masks, batch_first=True, padding_value=False, left_padding=left_padding)
+        batch_labels = self.pad_truncate_sequence(labels, batch_first=True, padding_value=IGNORE_ID, left_padding=left_padding)
+
+        return visual_input_ids, batch_input_embeds, batch_labels, batch_attention_mask
+
+    def pad_truncate_sequence(self, sequences: List[torch.Tensor], batch_first: bool = True, padding_value: float = 0.0, left_padding: bool = False) -> torch.Tensor:
+        if not left_padding:
+            pad_sequence = torch.nn.utils.rnn.pad_sequence(sequences, batch_first=batch_first, padding_value=padding_value)
+            return pad_sequence[:,:self.config.multimodal_max_length]
+        else:
+            pad_sequence = torch.nn.utils.rnn.pad_sequence([i.flip(dims=[0]) for i in sequences],batch_first=True, padding_value=padding_value).flip(dims=[1])
+            return pad_sequence[:,-self.config.multimodal_max_length:]
+
+    def preprocess_inputs(
+        self,
+        text_or_conversations: Union[List[Dict], str],
+        images: Optional[List[PIL.Image.Image]],
+        max_partition=9,
+        generation_preface='',
+        return_labels=False,
+        propagate_exception=True,
+        frame_selector=None,
+        frame_selector_kwargs=None
+    ):
+        # convert text to conversations
+        if isinstance(text_or_conversations, str):
+            conversations = [{
+                "from": "human",
+                "value": text_or_conversations
+            }]
+        elif isinstance(text_or_conversations, list):
+            conversations = text_or_conversations
+        else:
+            raise ValueError(f'Invalid type of `text_or_conversations`, expected `List[Dict]` or `str`,'
+                             f' but got {type(text_or_conversations)}')
+
+        if frame_selector is not None:
+            frame_selector_kwargs = frame_selector_kwargs or {}
+            conversations, images = frame_selector(conversations=conversations, frames=images, **frame_selector_kwargs)
+
+        # format conversations
+        prompt, raw_input_ids, raw_labels = self.get_conversation_formatter().format(
+            conversations, generation_preface=generation_preface)
+
+        # place image placeholders
+        input_ids = []
+        labels = []
+        pixel_values = []
+        invalidate_label = False
+        image_token_indices = [i for i, v in enumerate(raw_input_ids) if v == IMAGE_TOKEN_ID]
+        last_image_token_index = -1
+        for i in range(len(image_token_indices)):
+            head = 0 if i == 0 else image_token_indices[i - 1] + 1
+            tail = image_token_indices[i]
+            last_image_token_index = tail
+            input_ids.extend(raw_input_ids[head:tail])
+            labels.extend(raw_labels[head:tail])
+            try:
+                image = images[i]
+                raw_pixel_values, image_placeholders = self.visual_tokenizer.preprocess_image(
+                    image, max_partition=max_partition)
+            except Exception as e:
+                if propagate_exception:
+                    raise e
+                logging.exception(e)
+                invalidate_label = True
+                raw_pixel_values, image_placeholders = self.visual_tokenizer.mock_input()
+            input_ids.extend(image_placeholders)
+            labels.extend([IGNORE_ID] * len(image_placeholders))
+            pixel_values.append(raw_pixel_values)
+        input_ids.extend(raw_input_ids[last_image_token_index + 1:])
+        labels.extend(raw_labels[last_image_token_index + 1:])
+
+        # return tensors
+        input_ids = torch.tensor(input_ids, dtype=torch.long)
+        labels = torch.tensor([IGNORE_ID] * len(labels) if invalidate_label else labels, dtype=torch.long)
+        pixel_values = torch.cat(pixel_values, dim=0) if len(pixel_values) > 0 else None
+
+        if return_labels:
+            return prompt, input_ids, pixel_values, labels
+        else:
+            return prompt, input_ids, pixel_values
+
+    def save_pretrained(
+        self,
+        save_directory: Union[str, os.PathLike],
+        is_main_process: bool = True,
+        state_dict: Optional[dict] = None,
+        save_function: Callable = torch.save,
+        push_to_hub: bool = False,
+        max_shard_size: Union[int, str] = "5GB",
+        safe_serialization: bool = True,
+        variant: Optional[str] = None,
+        token: Optional[Union[str, bool]] = None,
+        save_peft_format: bool = True,
+        **kwargs
+    ):
+        super().save_pretrained(save_directory,
+                                is_main_process=is_main_process,
+                                state_dict=state_dict,
+                                save_function=save_function,
+                                safe_serialization=safe_serialization)
+        self.get_text_tokenizer().save_pretrained(save_directory)
+        self.get_visual_tokenizer().get_image_processor().save_pretrained(save_directory)
+
+    def generate(
+        self,
+        inputs: Optional[torch.Tensor] = None,
+        **kwargs
+    ) -> Union[GenerateOutput, torch.LongTensor]:
+        _, inputs_embeds, labels, attention_mask = self.merge_multimodal(
+            text_input_ids=inputs,
+            text_attention_masks=kwargs.pop('attention_mask'),
+            text_labels=None,
+            pixel_values=kwargs.pop('pixel_values'),
+            left_padding=True
+        )
+        inputs_embeds = inputs_embeds.detach()
+        torch.cuda.empty_cache()
+
+        return self.llm.generate(inputs=None, inputs_embeds=inputs_embeds, attention_mask=attention_mask, **kwargs)